Redmine

This description was written by one of my redmine users. I was able to reproduce the issue and i think its a bug in redmine (or firefox, im not absolutly sure):

I encountered a problem when using Firefox, in Opera it works properly. Because I know that some of you are using Firefox and some of you will work the same way as me (relying on many tabs when browsing) I will describe the issue here in order to inform about it.
The problem is that when you hit F5 or click the Reload button Firefox seems to update values of certain fields (see below which ones are affected) but when you click on the Update button in Redmine you still got old values to work with. Consequently when you are not careful you submit those old values to the system and overwriting newer values.

Steps to reproduce:
Computer A:
1. Open an existing ticket in Redmine.

Computer B:
2. Open the same ticket in Redmine.
3. Click on the Update button.
3. Change a value that is affected by the bug, e.g. Status and click the Submit button in order to send the changes to Redmine. In my example I changed the status from accepted to in progress.

Computer A:
4. Press F5 or click the Reload button in order to refresh the website.
5. Now in order to change something yourself you click on the Update button and as in my case suddenly the field Status retains the old value "accepted". Because not all values are affected you will see the notification

The following fields are affected by this behavior:
Status
Priority
Assignee
% Done
Category
Estimated time
Target version
Notes
Tracker

Not affected are:
Project
Subject
Description Edit
Parent Task
Start Date
Due Date

Workaround:
Press Shift + Reload button (F5) or reenter the URL in the browser in Firefox
OR use the Opera web browser